blob: 495611b7068dc42bf2cbddfb3c86e4711d4badab [file] [log] [blame]
Chris Wilson688e6c72016-07-01 17:23:15 +01001/*
2 * Copyright © 2015 Intel Corporation
3 *
4 * Permission is hereby granted, free of charge, to any person obtaining a
5 * copy of this software and associated documentation files (the "Software"),
6 * to deal in the Software without restriction, including without limitation
7 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
8 * and/or sell copies of the Software, and to permit persons to whom the
9 * Software is furnished to do so, subject to the following conditions:
10 *
11 * The above copyright notice and this permission notice (including the next
12 * paragraph) shall be included in all copies or substantial portions of the
13 * Software.
14 *
15 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
16 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
17 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
18 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
19 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
20 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
21 * IN THE SOFTWARE.
22 *
23 */
24
Chris Wilsonc81d4612016-07-01 17:23:25 +010025#include <linux/kthread.h>
26
Chris Wilson688e6c72016-07-01 17:23:15 +010027#include "i915_drv.h"
28
Chris Wilson83348ba2016-08-09 17:47:51 +010029static void intel_breadcrumbs_hangcheck(unsigned long data)
30{
31 struct intel_engine_cs *engine = (struct intel_engine_cs *)data;
32 struct intel_breadcrumbs *b = &engine->breadcrumbs;
33
34 if (!b->irq_enabled)
35 return;
36
37 if (time_before(jiffies, b->timeout)) {
38 mod_timer(&b->hangcheck, b->timeout);
39 return;
40 }
41
42 DRM_DEBUG("Hangcheck timer elapsed... %s idle\n", engine->name);
43 set_bit(engine->id, &engine->i915->gpu_error.missed_irq_rings);
44 mod_timer(&engine->breadcrumbs.fake_irq, jiffies + 1);
45
46 /* Ensure that even if the GPU hangs, we get woken up.
47 *
48 * However, note that if no one is waiting, we never notice
49 * a gpu hang. Eventually, we will have to wait for a resource
50 * held by the GPU and so trigger a hangcheck. In the most
51 * pathological case, this will be upon memory starvation! To
52 * prevent this, we also queue the hangcheck from the retire
53 * worker.
54 */
55 i915_queue_hangcheck(engine->i915);
56}
57
58static unsigned long wait_timeout(void)
59{
60 return round_jiffies_up(jiffies + DRM_I915_HANGCHECK_JIFFIES);
61}
62
Chris Wilson688e6c72016-07-01 17:23:15 +010063static void intel_breadcrumbs_fake_irq(unsigned long data)
64{
65 struct intel_engine_cs *engine = (struct intel_engine_cs *)data;
66
67 /*
68 * The timer persists in case we cannot enable interrupts,
69 * or if we have previously seen seqno/interrupt incoherency
70 * ("missed interrupt" syndrome). Here the worker will wake up
71 * every jiffie in order to kick the oldest waiter to do the
72 * coherent seqno check.
73 */
Chris Wilson688e6c72016-07-01 17:23:15 +010074 if (intel_engine_wakeup(engine))
75 mod_timer(&engine->breadcrumbs.fake_irq, jiffies + 1);
Chris Wilson688e6c72016-07-01 17:23:15 +010076}
77
78static void irq_enable(struct intel_engine_cs *engine)
79{
Chris Wilson3d5564e2016-07-01 17:23:23 +010080 /* Enabling the IRQ may miss the generation of the interrupt, but
81 * we still need to force the barrier before reading the seqno,
82 * just in case.
83 */
Chris Wilsonaca34b62016-07-06 12:39:02 +010084 engine->breadcrumbs.irq_posted = true;
Chris Wilson31bb59c2016-07-01 17:23:27 +010085
86 spin_lock_irq(&engine->i915->irq_lock);
87 engine->irq_enable(engine);
88 spin_unlock_irq(&engine->i915->irq_lock);
Chris Wilson688e6c72016-07-01 17:23:15 +010089}
90
91static void irq_disable(struct intel_engine_cs *engine)
92{
Chris Wilson31bb59c2016-07-01 17:23:27 +010093 spin_lock_irq(&engine->i915->irq_lock);
94 engine->irq_disable(engine);
95 spin_unlock_irq(&engine->i915->irq_lock);
96
Chris Wilsonaca34b62016-07-06 12:39:02 +010097 engine->breadcrumbs.irq_posted = false;
Chris Wilson688e6c72016-07-01 17:23:15 +010098}
99
Chris Wilson04171312016-07-06 12:39:00 +0100100static void __intel_breadcrumbs_enable_irq(struct intel_breadcrumbs *b)
Chris Wilson688e6c72016-07-01 17:23:15 +0100101{
102 struct intel_engine_cs *engine =
103 container_of(b, struct intel_engine_cs, breadcrumbs);
104 struct drm_i915_private *i915 = engine->i915;
Chris Wilson688e6c72016-07-01 17:23:15 +0100105
106 assert_spin_locked(&b->lock);
107 if (b->rpm_wakelock)
Chris Wilson04171312016-07-06 12:39:00 +0100108 return;
Chris Wilson688e6c72016-07-01 17:23:15 +0100109
110 /* Since we are waiting on a request, the GPU should be busy
111 * and should have its own rpm reference. For completeness,
112 * record an rpm reference for ourselves to cover the
113 * interrupt we unmask.
114 */
115 intel_runtime_pm_get_noresume(i915);
116 b->rpm_wakelock = true;
117
118 /* No interrupts? Kick the waiter every jiffie! */
119 if (intel_irqs_enabled(i915)) {
Chris Wilson3d5564e2016-07-01 17:23:23 +0100120 if (!test_bit(engine->id, &i915->gpu_error.test_irq_rings))
Chris Wilson688e6c72016-07-01 17:23:15 +0100121 irq_enable(engine);
Chris Wilson688e6c72016-07-01 17:23:15 +0100122 b->irq_enabled = true;
123 }
124
125 if (!b->irq_enabled ||
Chris Wilson83348ba2016-08-09 17:47:51 +0100126 test_bit(engine->id, &i915->gpu_error.missed_irq_rings)) {
Chris Wilson688e6c72016-07-01 17:23:15 +0100127 mod_timer(&b->fake_irq, jiffies + 1);
Chris Wilson83348ba2016-08-09 17:47:51 +0100128 } else {
129 /* Ensure we never sleep indefinitely */
130 GEM_BUG_ON(!time_after(b->timeout, jiffies));
131 mod_timer(&b->hangcheck, b->timeout);
132 }
Chris Wilson688e6c72016-07-01 17:23:15 +0100133}
134
135static void __intel_breadcrumbs_disable_irq(struct intel_breadcrumbs *b)
136{
137 struct intel_engine_cs *engine =
138 container_of(b, struct intel_engine_cs, breadcrumbs);
139
140 assert_spin_locked(&b->lock);
141 if (!b->rpm_wakelock)
142 return;
143
144 if (b->irq_enabled) {
145 irq_disable(engine);
146 b->irq_enabled = false;
147 }
148
149 intel_runtime_pm_put(engine->i915);
150 b->rpm_wakelock = false;
151}
152
153static inline struct intel_wait *to_wait(struct rb_node *node)
154{
155 return container_of(node, struct intel_wait, node);
156}
157
158static inline void __intel_breadcrumbs_finish(struct intel_breadcrumbs *b,
159 struct intel_wait *wait)
160{
161 assert_spin_locked(&b->lock);
162
163 /* This request is completed, so remove it from the tree, mark it as
164 * complete, and *then* wake up the associated task.
165 */
166 rb_erase(&wait->node, &b->waiters);
167 RB_CLEAR_NODE(&wait->node);
168
169 wake_up_process(wait->tsk); /* implicit smp_wmb() */
170}
171
172static bool __intel_engine_add_wait(struct intel_engine_cs *engine,
173 struct intel_wait *wait)
174{
175 struct intel_breadcrumbs *b = &engine->breadcrumbs;
176 struct rb_node **p, *parent, *completed;
177 bool first;
178 u32 seqno;
179
180 /* Insert the request into the retirement ordered list
181 * of waiters by walking the rbtree. If we are the oldest
182 * seqno in the tree (the first to be retired), then
183 * set ourselves as the bottom-half.
184 *
185 * As we descend the tree, prune completed branches since we hold the
186 * spinlock we know that the first_waiter must be delayed and can
187 * reduce some of the sequential wake up latency if we take action
188 * ourselves and wake up the completed tasks in parallel. Also, by
189 * removing stale elements in the tree, we may be able to reduce the
190 * ping-pong between the old bottom-half and ourselves as first-waiter.
191 */
192 first = true;
193 parent = NULL;
194 completed = NULL;
Chris Wilson1b7744e2016-07-01 17:23:17 +0100195 seqno = intel_engine_get_seqno(engine);
Chris Wilson688e6c72016-07-01 17:23:15 +0100196
197 /* If the request completed before we managed to grab the spinlock,
198 * return now before adding ourselves to the rbtree. We let the
199 * current bottom-half handle any pending wakeups and instead
200 * try and get out of the way quickly.
201 */
202 if (i915_seqno_passed(seqno, wait->seqno)) {
203 RB_CLEAR_NODE(&wait->node);
204 return first;
205 }
206
207 p = &b->waiters.rb_node;
208 while (*p) {
209 parent = *p;
210 if (wait->seqno == to_wait(parent)->seqno) {
211 /* We have multiple waiters on the same seqno, select
212 * the highest priority task (that with the smallest
213 * task->prio) to serve as the bottom-half for this
214 * group.
215 */
216 if (wait->tsk->prio > to_wait(parent)->tsk->prio) {
217 p = &parent->rb_right;
218 first = false;
219 } else {
220 p = &parent->rb_left;
221 }
222 } else if (i915_seqno_passed(wait->seqno,
223 to_wait(parent)->seqno)) {
224 p = &parent->rb_right;
225 if (i915_seqno_passed(seqno, to_wait(parent)->seqno))
226 completed = parent;
227 else
228 first = false;
229 } else {
230 p = &parent->rb_left;
231 }
232 }
233 rb_link_node(&wait->node, parent, p);
234 rb_insert_color(&wait->node, &b->waiters);
Chris Wilsondbd6ef22016-08-09 17:47:52 +0100235 GEM_BUG_ON(!first && !rcu_access_pointer(b->irq_seqno_bh));
Chris Wilson688e6c72016-07-01 17:23:15 +0100236
237 if (completed) {
238 struct rb_node *next = rb_next(completed);
239
240 GEM_BUG_ON(!next && !first);
241 if (next && next != &wait->node) {
242 GEM_BUG_ON(first);
Chris Wilson83348ba2016-08-09 17:47:51 +0100243 b->timeout = wait_timeout();
Chris Wilson688e6c72016-07-01 17:23:15 +0100244 b->first_wait = to_wait(next);
Chris Wilsondbd6ef22016-08-09 17:47:52 +0100245 rcu_assign_pointer(b->irq_seqno_bh, b->first_wait->tsk);
Chris Wilson688e6c72016-07-01 17:23:15 +0100246 /* As there is a delay between reading the current
247 * seqno, processing the completed tasks and selecting
248 * the next waiter, we may have missed the interrupt
249 * and so need for the next bottom-half to wakeup.
250 *
251 * Also as we enable the IRQ, we may miss the
252 * interrupt for that seqno, so we have to wake up
253 * the next bottom-half in order to do a coherent check
254 * in case the seqno passed.
255 */
256 __intel_breadcrumbs_enable_irq(b);
Chris Wilsonaca34b62016-07-06 12:39:02 +0100257 if (READ_ONCE(b->irq_posted))
Chris Wilson3d5564e2016-07-01 17:23:23 +0100258 wake_up_process(to_wait(next)->tsk);
Chris Wilson688e6c72016-07-01 17:23:15 +0100259 }
260
261 do {
262 struct intel_wait *crumb = to_wait(completed);
263 completed = rb_prev(completed);
264 __intel_breadcrumbs_finish(b, crumb);
265 } while (completed);
266 }
267
268 if (first) {
269 GEM_BUG_ON(rb_first(&b->waiters) != &wait->node);
Chris Wilson83348ba2016-08-09 17:47:51 +0100270 b->timeout = wait_timeout();
Chris Wilson688e6c72016-07-01 17:23:15 +0100271 b->first_wait = wait;
Chris Wilsondbd6ef22016-08-09 17:47:52 +0100272 rcu_assign_pointer(b->irq_seqno_bh, wait->tsk);
Chris Wilson04171312016-07-06 12:39:00 +0100273 /* After assigning ourselves as the new bottom-half, we must
274 * perform a cursory check to prevent a missed interrupt.
275 * Either we miss the interrupt whilst programming the hardware,
276 * or if there was a previous waiter (for a later seqno) they
277 * may be woken instead of us (due to the inherent race
Chris Wilsonaca34b62016-07-06 12:39:02 +0100278 * in the unlocked read of b->irq_seqno_bh in the irq handler)
279 * and so we miss the wake up.
Chris Wilson04171312016-07-06 12:39:00 +0100280 */
281 __intel_breadcrumbs_enable_irq(b);
Chris Wilson688e6c72016-07-01 17:23:15 +0100282 }
Chris Wilsondbd6ef22016-08-09 17:47:52 +0100283 GEM_BUG_ON(!rcu_access_pointer(b->irq_seqno_bh));
Chris Wilson688e6c72016-07-01 17:23:15 +0100284 GEM_BUG_ON(!b->first_wait);
285 GEM_BUG_ON(rb_first(&b->waiters) != &b->first_wait->node);
286
287 return first;
288}
289
290bool intel_engine_add_wait(struct intel_engine_cs *engine,
291 struct intel_wait *wait)
292{
293 struct intel_breadcrumbs *b = &engine->breadcrumbs;
294 bool first;
295
296 spin_lock(&b->lock);
297 first = __intel_engine_add_wait(engine, wait);
298 spin_unlock(&b->lock);
299
300 return first;
301}
302
Chris Wilson688e6c72016-07-01 17:23:15 +0100303static inline bool chain_wakeup(struct rb_node *rb, int priority)
304{
305 return rb && to_wait(rb)->tsk->prio <= priority;
306}
307
Chris Wilsonc81d4612016-07-01 17:23:25 +0100308static inline int wakeup_priority(struct intel_breadcrumbs *b,
309 struct task_struct *tsk)
310{
311 if (tsk == b->signaler)
312 return INT_MIN;
313 else
314 return tsk->prio;
315}
316
Chris Wilson688e6c72016-07-01 17:23:15 +0100317void intel_engine_remove_wait(struct intel_engine_cs *engine,
318 struct intel_wait *wait)
319{
320 struct intel_breadcrumbs *b = &engine->breadcrumbs;
321
322 /* Quick check to see if this waiter was already decoupled from
323 * the tree by the bottom-half to avoid contention on the spinlock
324 * by the herd.
325 */
326 if (RB_EMPTY_NODE(&wait->node))
327 return;
328
329 spin_lock(&b->lock);
330
331 if (RB_EMPTY_NODE(&wait->node))
332 goto out_unlock;
333
334 if (b->first_wait == wait) {
Chris Wilsonc81d4612016-07-01 17:23:25 +0100335 const int priority = wakeup_priority(b, wait->tsk);
Chris Wilson688e6c72016-07-01 17:23:15 +0100336 struct rb_node *next;
Chris Wilson688e6c72016-07-01 17:23:15 +0100337
Chris Wilsondbd6ef22016-08-09 17:47:52 +0100338 GEM_BUG_ON(rcu_access_pointer(b->irq_seqno_bh) != wait->tsk);
Chris Wilson688e6c72016-07-01 17:23:15 +0100339
340 /* We are the current bottom-half. Find the next candidate,
341 * the first waiter in the queue on the remaining oldest
342 * request. As multiple seqnos may complete in the time it
343 * takes us to wake up and find the next waiter, we have to
344 * wake up that waiter for it to perform its own coherent
345 * completion check.
346 */
347 next = rb_next(&wait->node);
348 if (chain_wakeup(next, priority)) {
349 /* If the next waiter is already complete,
350 * wake it up and continue onto the next waiter. So
351 * if have a small herd, they will wake up in parallel
352 * rather than sequentially, which should reduce
353 * the overall latency in waking all the completed
354 * clients.
355 *
356 * However, waking up a chain adds extra latency to
357 * the first_waiter. This is undesirable if that
358 * waiter is a high priority task.
359 */
Chris Wilson1b7744e2016-07-01 17:23:17 +0100360 u32 seqno = intel_engine_get_seqno(engine);
Chris Wilson688e6c72016-07-01 17:23:15 +0100361
362 while (i915_seqno_passed(seqno, to_wait(next)->seqno)) {
363 struct rb_node *n = rb_next(next);
364
365 __intel_breadcrumbs_finish(b, to_wait(next));
366 next = n;
367 if (!chain_wakeup(next, priority))
368 break;
369 }
370 }
371
372 if (next) {
373 /* In our haste, we may have completed the first waiter
374 * before we enabled the interrupt. Do so now as we
375 * have a second waiter for a future seqno. Afterwards,
376 * we have to wake up that waiter in case we missed
377 * the interrupt, or if we have to handle an
378 * exception rather than a seqno completion.
379 */
Chris Wilson83348ba2016-08-09 17:47:51 +0100380 b->timeout = wait_timeout();
Chris Wilson688e6c72016-07-01 17:23:15 +0100381 b->first_wait = to_wait(next);
Chris Wilsondbd6ef22016-08-09 17:47:52 +0100382 rcu_assign_pointer(b->irq_seqno_bh, b->first_wait->tsk);
Chris Wilson688e6c72016-07-01 17:23:15 +0100383 if (b->first_wait->seqno != wait->seqno)
384 __intel_breadcrumbs_enable_irq(b);
Chris Wilsondbd6ef22016-08-09 17:47:52 +0100385 wake_up_process(b->first_wait->tsk);
Chris Wilson688e6c72016-07-01 17:23:15 +0100386 } else {
387 b->first_wait = NULL;
Chris Wilsondbd6ef22016-08-09 17:47:52 +0100388 rcu_assign_pointer(b->irq_seqno_bh, NULL);
Chris Wilson688e6c72016-07-01 17:23:15 +0100389 __intel_breadcrumbs_disable_irq(b);
390 }
391 } else {
392 GEM_BUG_ON(rb_first(&b->waiters) == &wait->node);
393 }
394
395 GEM_BUG_ON(RB_EMPTY_NODE(&wait->node));
396 rb_erase(&wait->node, &b->waiters);
397
398out_unlock:
399 GEM_BUG_ON(b->first_wait == wait);
400 GEM_BUG_ON(rb_first(&b->waiters) !=
401 (b->first_wait ? &b->first_wait->node : NULL));
Chris Wilsondbd6ef22016-08-09 17:47:52 +0100402 GEM_BUG_ON(!rcu_access_pointer(b->irq_seqno_bh) ^ RB_EMPTY_ROOT(&b->waiters));
Chris Wilson688e6c72016-07-01 17:23:15 +0100403 spin_unlock(&b->lock);
404}
405
Chris Wilsonb3850852016-07-01 17:23:26 +0100406static bool signal_complete(struct drm_i915_gem_request *request)
Chris Wilsonc81d4612016-07-01 17:23:25 +0100407{
Chris Wilsonb3850852016-07-01 17:23:26 +0100408 if (!request)
Chris Wilsonc81d4612016-07-01 17:23:25 +0100409 return false;
410
411 /* If another process served as the bottom-half it may have already
412 * signalled that this wait is already completed.
413 */
Chris Wilsonb3850852016-07-01 17:23:26 +0100414 if (intel_wait_complete(&request->signaling.wait))
Chris Wilsonc81d4612016-07-01 17:23:25 +0100415 return true;
416
417 /* Carefully check if the request is complete, giving time for the
418 * seqno to be visible or if the GPU hung.
419 */
Chris Wilsonb3850852016-07-01 17:23:26 +0100420 if (__i915_request_irq_complete(request))
Chris Wilsonc81d4612016-07-01 17:23:25 +0100421 return true;
422
423 return false;
424}
425
Chris Wilsonb3850852016-07-01 17:23:26 +0100426static struct drm_i915_gem_request *to_signaler(struct rb_node *rb)
Chris Wilsonc81d4612016-07-01 17:23:25 +0100427{
Chris Wilsonb3850852016-07-01 17:23:26 +0100428 return container_of(rb, struct drm_i915_gem_request, signaling.node);
Chris Wilsonc81d4612016-07-01 17:23:25 +0100429}
430
431static void signaler_set_rtpriority(void)
432{
433 struct sched_param param = { .sched_priority = 1 };
434
435 sched_setscheduler_nocheck(current, SCHED_FIFO, &param);
436}
437
438static int intel_breadcrumbs_signaler(void *arg)
439{
440 struct intel_engine_cs *engine = arg;
441 struct intel_breadcrumbs *b = &engine->breadcrumbs;
Chris Wilsonb3850852016-07-01 17:23:26 +0100442 struct drm_i915_gem_request *request;
Chris Wilsonc81d4612016-07-01 17:23:25 +0100443
444 /* Install ourselves with high priority to reduce signalling latency */
445 signaler_set_rtpriority();
446
447 do {
448 set_current_state(TASK_INTERRUPTIBLE);
449
450 /* We are either woken up by the interrupt bottom-half,
451 * or by a client adding a new signaller. In both cases,
452 * the GPU seqno may have advanced beyond our oldest signal.
453 * If it has, propagate the signal, remove the waiter and
454 * check again with the next oldest signal. Otherwise we
455 * need to wait for a new interrupt from the GPU or for
456 * a new client.
457 */
Chris Wilsonb3850852016-07-01 17:23:26 +0100458 request = READ_ONCE(b->first_signal);
459 if (signal_complete(request)) {
Chris Wilsonc81d4612016-07-01 17:23:25 +0100460 /* Wake up all other completed waiters and select the
461 * next bottom-half for the next user interrupt.
462 */
Chris Wilsonb3850852016-07-01 17:23:26 +0100463 intel_engine_remove_wait(engine,
464 &request->signaling.wait);
Chris Wilson5590af32016-09-09 14:11:54 +0100465
466 local_bh_disable();
Chris Wilson04769652016-07-20 09:21:11 +0100467 fence_signal(&request->fence);
Chris Wilson5590af32016-09-09 14:11:54 +0100468 local_bh_enable(); /* kick start the tasklets */
Chris Wilsonc81d4612016-07-01 17:23:25 +0100469
470 /* Find the next oldest signal. Note that as we have
471 * not been holding the lock, another client may
472 * have installed an even older signal than the one
473 * we just completed - so double check we are still
474 * the oldest before picking the next one.
475 */
476 spin_lock(&b->lock);
Chris Wilsonb3850852016-07-01 17:23:26 +0100477 if (request == b->first_signal) {
478 struct rb_node *rb =
479 rb_next(&request->signaling.node);
480 b->first_signal = rb ? to_signaler(rb) : NULL;
481 }
482 rb_erase(&request->signaling.node, &b->signals);
Chris Wilsonc81d4612016-07-01 17:23:25 +0100483 spin_unlock(&b->lock);
484
Chris Wilsone8a261e2016-07-20 13:31:49 +0100485 i915_gem_request_put(request);
Chris Wilsonc81d4612016-07-01 17:23:25 +0100486 } else {
487 if (kthread_should_stop())
488 break;
489
490 schedule();
491 }
492 } while (1);
493 __set_current_state(TASK_RUNNING);
494
495 return 0;
496}
497
Chris Wilsonb3850852016-07-01 17:23:26 +0100498void intel_engine_enable_signaling(struct drm_i915_gem_request *request)
Chris Wilsonc81d4612016-07-01 17:23:25 +0100499{
500 struct intel_engine_cs *engine = request->engine;
501 struct intel_breadcrumbs *b = &engine->breadcrumbs;
502 struct rb_node *parent, **p;
Chris Wilsonc81d4612016-07-01 17:23:25 +0100503 bool first, wakeup;
504
Chris Wilson4a50d202016-07-26 12:01:50 +0100505 /* locked by fence_enable_sw_signaling() */
506 assert_spin_locked(&request->lock);
Chris Wilsonc81d4612016-07-01 17:23:25 +0100507
Chris Wilsonb3850852016-07-01 17:23:26 +0100508 request->signaling.wait.tsk = b->signaler;
Chris Wilson04769652016-07-20 09:21:11 +0100509 request->signaling.wait.seqno = request->fence.seqno;
Chris Wilsone8a261e2016-07-20 13:31:49 +0100510 i915_gem_request_get(request);
Chris Wilsonc81d4612016-07-01 17:23:25 +0100511
Chris Wilson4a50d202016-07-26 12:01:50 +0100512 spin_lock(&b->lock);
513
Chris Wilsonc81d4612016-07-01 17:23:25 +0100514 /* First add ourselves into the list of waiters, but register our
515 * bottom-half as the signaller thread. As per usual, only the oldest
516 * waiter (not just signaller) is tasked as the bottom-half waking
517 * up all completed waiters after the user interrupt.
518 *
519 * If we are the oldest waiter, enable the irq (after which we
520 * must double check that the seqno did not complete).
521 */
Chris Wilsonb3850852016-07-01 17:23:26 +0100522 wakeup = __intel_engine_add_wait(engine, &request->signaling.wait);
Chris Wilsonc81d4612016-07-01 17:23:25 +0100523
524 /* Now insert ourselves into the retirement ordered list of signals
525 * on this engine. We track the oldest seqno as that will be the
526 * first signal to complete.
527 */
Chris Wilsonc81d4612016-07-01 17:23:25 +0100528 parent = NULL;
529 first = true;
530 p = &b->signals.rb_node;
531 while (*p) {
532 parent = *p;
Chris Wilson04769652016-07-20 09:21:11 +0100533 if (i915_seqno_passed(request->fence.seqno,
534 to_signaler(parent)->fence.seqno)) {
Chris Wilsonc81d4612016-07-01 17:23:25 +0100535 p = &parent->rb_right;
536 first = false;
537 } else {
538 p = &parent->rb_left;
539 }
540 }
Chris Wilsonb3850852016-07-01 17:23:26 +0100541 rb_link_node(&request->signaling.node, parent, p);
542 rb_insert_color(&request->signaling.node, &b->signals);
Chris Wilsonc81d4612016-07-01 17:23:25 +0100543 if (first)
Chris Wilsonb3850852016-07-01 17:23:26 +0100544 smp_store_mb(b->first_signal, request);
545
Chris Wilsonc81d4612016-07-01 17:23:25 +0100546 spin_unlock(&b->lock);
547
548 if (wakeup)
549 wake_up_process(b->signaler);
Chris Wilsonc81d4612016-07-01 17:23:25 +0100550}
551
Chris Wilson688e6c72016-07-01 17:23:15 +0100552int intel_engine_init_breadcrumbs(struct intel_engine_cs *engine)
553{
554 struct intel_breadcrumbs *b = &engine->breadcrumbs;
Chris Wilsonc81d4612016-07-01 17:23:25 +0100555 struct task_struct *tsk;
Chris Wilson688e6c72016-07-01 17:23:15 +0100556
557 spin_lock_init(&b->lock);
558 setup_timer(&b->fake_irq,
559 intel_breadcrumbs_fake_irq,
560 (unsigned long)engine);
Chris Wilson83348ba2016-08-09 17:47:51 +0100561 setup_timer(&b->hangcheck,
562 intel_breadcrumbs_hangcheck,
563 (unsigned long)engine);
Chris Wilson688e6c72016-07-01 17:23:15 +0100564
Chris Wilsonc81d4612016-07-01 17:23:25 +0100565 /* Spawn a thread to provide a common bottom-half for all signals.
566 * As this is an asynchronous interface we cannot steal the current
567 * task for handling the bottom-half to the user interrupt, therefore
568 * we create a thread to do the coherent seqno dance after the
569 * interrupt and then signal the waitqueue (via the dma-buf/fence).
570 */
571 tsk = kthread_run(intel_breadcrumbs_signaler, engine,
572 "i915/signal:%d", engine->id);
573 if (IS_ERR(tsk))
574 return PTR_ERR(tsk);
575
576 b->signaler = tsk;
577
Chris Wilson688e6c72016-07-01 17:23:15 +0100578 return 0;
579}
580
Chris Wilson61a05872016-10-07 07:53:26 +0100581static void cancel_fake_irq(struct intel_engine_cs *engine)
582{
583 struct intel_breadcrumbs *b = &engine->breadcrumbs;
584
585 del_timer_sync(&b->hangcheck);
586 del_timer_sync(&b->fake_irq);
587 clear_bit(engine->id, &engine->i915->gpu_error.missed_irq_rings);
588}
589
590void intel_engine_reset_breadcrumbs(struct intel_engine_cs *engine)
591{
592 struct intel_breadcrumbs *b = &engine->breadcrumbs;
593
594 cancel_fake_irq(engine);
595 spin_lock(&b->lock);
596
597 __intel_breadcrumbs_disable_irq(b);
598 if (intel_engine_has_waiter(engine)) {
599 b->timeout = wait_timeout();
600 __intel_breadcrumbs_enable_irq(b);
601 if (READ_ONCE(b->irq_posted))
602 wake_up_process(b->first_wait->tsk);
603 } else {
604 /* sanitize the IMR and unmask any auxiliary interrupts */
605 irq_disable(engine);
606 }
607
608 spin_unlock(&b->lock);
609}
610
Chris Wilson688e6c72016-07-01 17:23:15 +0100611void intel_engine_fini_breadcrumbs(struct intel_engine_cs *engine)
612{
613 struct intel_breadcrumbs *b = &engine->breadcrumbs;
614
Chris Wilsonc81d4612016-07-01 17:23:25 +0100615 if (!IS_ERR_OR_NULL(b->signaler))
616 kthread_stop(b->signaler);
617
Chris Wilson61a05872016-10-07 07:53:26 +0100618 cancel_fake_irq(engine);
Chris Wilson688e6c72016-07-01 17:23:15 +0100619}
620
621unsigned int intel_kick_waiters(struct drm_i915_private *i915)
622{
623 struct intel_engine_cs *engine;
624 unsigned int mask = 0;
625
626 /* To avoid the task_struct disappearing beneath us as we wake up
627 * the process, we must first inspect the task_struct->state under the
628 * RCU lock, i.e. as we call wake_up_process() we must be holding the
629 * rcu_read_lock().
630 */
Chris Wilson688e6c72016-07-01 17:23:15 +0100631 for_each_engine(engine, i915)
632 if (unlikely(intel_engine_wakeup(engine)))
633 mask |= intel_engine_flag(engine);
Chris Wilson688e6c72016-07-01 17:23:15 +0100634
635 return mask;
636}
Chris Wilsonc81d4612016-07-01 17:23:25 +0100637
638unsigned int intel_kick_signalers(struct drm_i915_private *i915)
639{
640 struct intel_engine_cs *engine;
641 unsigned int mask = 0;
642
643 for_each_engine(engine, i915) {
644 if (unlikely(READ_ONCE(engine->breadcrumbs.first_signal))) {
645 wake_up_process(engine->breadcrumbs.signaler);
646 mask |= intel_engine_flag(engine);
647 }
648 }
649
650 return mask;
651}